Materials Data on Co2NiSe4 by Materials Project
Co2NiSe4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Co3+ is bonded to six Se2- atoms to form CoSe6 octahedra that share corners with six equivalent NiSe6 octahedra, edges with six equivalent CoSe6 octahedra, and a faceface with one NiSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–54°. There are a spread of Co–Se bond distances ranging from 2.35–2.48 Å. Ni2+ is bonded to six Se2- atoms to form NiSe6 octahedra that share corners with twelve equivalent CoSe6 octahedra, edges with two equivalent NiSe6 octahedra, and faces with two equivalent CoSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–54°. There are two shorter (2.47 Å) and four longer (2.49 Å) Ni–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to three equivalent Co3+ and two equivalent Ni2+ atoms. In the second Se2- site, Se2- is bonded to three equivalent Co3+ and one Ni2+ atom to form a mixture of distorted edge and corner-sharing SeCo3Ni trigonal pyramids.